Oxidative Stress in HPV-Driven Viral Carcinogenesis: Redox Proteomics Analysis of HPV-16 Dysplastic and Neoplastic Tissues

Abstract

Genital infection by high risk Human Papillomavirus (HR-HPV), although recognized as the main etio-pathogenetic factor of cervical cancer, is not per se sufficient to induce tumour development. Oxidative stress (OS) represents an interesting and under-explored candidate as a promoting factor in HPV-initiated carcinogenesis. To gain insight into the role of OS in cervical cancer, HPV-16 positive tissues were collected from patients with invasive squamous cervical carcinoma, from patients with High Grade dysplastic HPV lesions and from patients with no clinical evidence of HPV lesions. After virological characterization, modulation of proteins involved in the redox status regulation was investigated. ERp57 and GST were sharply elevated in dysplastic and neoplastic tissues. TrxR2 peaked in dysplastic samples while iNOS was progressively reduced in dysplastic and neoplastic samples. By redox proteomic approach, five proteins were found to have increased levels of carbonyls in dysplastic samples respect to controls namely: cytokeratin 6, actin, cornulin, retinal dehydrogenase and GAPDH. In carcinoma samples the peptidyl-prolyl cis-trans isomerase A, ERp57, serpin B3, Annexin 2 and GAPDH were found less oxidized than in dysplastic tissues. HPV16 neoplastic progression seems associated with increased oxidant environment. In dysplastic tissues the oxidative modification of DNA and proteins involved in cell morphogenesis and terminal differentiation may provide the conditions for the neoplastic progression. Conversely cancer tissues seem to attain an improved control on oxidative damage as shown by the selective reduction of carbonyl adducts on key detoxifying/pro-survival proteins.

Proteomic identification of potential biomarkers for cervical squamous cell carcinoma and human papillomavirus infection

“…28,29 In addition, redox proteomics identified the differential expression of ERp57, GST, TrxR2, and iNOS as a biomarker profile for HPV-positive invasive cervical carcinoma. 30 However, HPV genotyping was often not performed or considered in previous proteomics studies of cervical carcinoma. In our study, the protein expression pattern of HPV16-positive tumor specimens was compared with that of HPV-negative NC from the uterine cervix by 8-plex iTRAQ proteomics.…”

“…38,39 CRNN is a marker of late epidermal differentiation and is downregulated in cervical lesions. 25,30 FBN/LTPB is a calcium-binding protein of the extracellular matrix, and overexpression of FBN2 but not FBN1 has been reported in cervical adenocarcinoma. 40 LUM is a small leucine-rich proteoglycan expressed in the periphery of cancer nests of cervical SCC.…”

PDIA3 and PDIA6 gene expression as an aggressiveness marker in primary ductal breast cancer

“…It has also been linked to DNA repair as a member of the damage recognition complex and as a potential regulator that binds to genes with recognized repair functions (Chichiarelli et al, 2007). Several studies have linked PDIs to different types of cancer, including gastric (Leys et al, 2007), prostate (Pressinotti et al, 2009), esophageal (Ayshamgul et al, 2011), cervical (De Marco et al, 2012;Chung et al, 2013), salivary gland (Müller et al, 2013), bone metastasis (Santana-Codina et al, 2013), and breast (Lee et al, 2012;Gaucci et al, 2013) cancers. Another gene in this superfamily, PDIA6, also encodes a product that exhibits chaperone activity by inhibiting misformed protein aggregation.…”

Ellagic acid and Annona muricata in the chemoprevention of HPV-related pre-neoplastic lesions of the cervix

“…The progression from mild dysplasia to severe dysplasia, and onwards to invasive cancer, is promoted by increasing levels of oxidative stress (27,28). Proteomics analysis of HPV-16 infected tissues have indicated that dysplasia is characterized by an increased oxidative environment compared to normal or neoplastic tissue, resulting in the oxidative modification of DNA and proteins involved in cell morphogenesis and terminal differentiation, thus providing ideal conditions for disease progression and cancer (28). The use of antioxidants including ellagic acid and Annona muricata may counterbalance the damaging effects of oxidative stress by arresting the cell cycle, promoting DNA repair and inducing apoptosis, thus hampering disease progression.…”